Golf club shaft grip

ABSTRACT

A golf club shaft grip having a polyurethane layer bonded to a felt layer. The bonded-together layers are configured as a strip which is spirally wrapped about the shaft. A cap is then telescopically applied over the upper end of the shaft to prevent unraveling of the strip from the shaft.

This application is a Continuation-In-Part of application Ser. No.08/567,339 filed Dec. 28, 1995, abandoned, and a Division of applicationSer. No. 08/632,578 filed Apr. 15, 1996, now U.S. Pat. No. 5,671,923.

BACKGROUND OF THE INVENTION

The present invention relates to an improved golf club shaft grip.

It is well known that shock generated by impact between a golf club anda golf ball can adversely affect muscle tissue and arm joints such aselbow joints. The energy generated by such shock is usually of highfrequency and short duration with rapid decay, and which is often knownas "impact shock." Tight grasping of a grip to keep it from slippingcontributes to the shock to the muscle tissue and arm joints of theusers golf clubs.

Prior art golf club shaft grips have utilized a layer of polyurethanebacked with a layer of felt. In general, the felt layer has a thicknessof about 1.40 mm. The polyurethane layer is generally thinner than 0.25mm, and has been considered only as providing tackiness, i.e.,resistance to the slip caused by a sweaty hand. The polyurethane has notbeen considered to be useful for inhibiting shock. The felt was reliedupon to cushion the user's arm and hand against the shock created whenthe club strikes the ball.

Applicant has previously developed resilient grips which successfullyreduce shock to the muscle and arm joints of the users of golf clubs,tennis racquets, racquet ball racquets, baseball bats, and other impactimparting devices such as hammers. See, for example, U.S. Pat. No.5,374,059 granted to applicant Dec. 20, 1994. Such earlier grips utilizea polyurethane layer bonded to a felt layer to define a strip which isspirally wrapped around the handle of a golf club or racquet to conformto the external configuration of such handle. In such earlier grips ofapplicant's design the thickness of the polyurethane layer relative tothe thickness of the felt layer as compared to prior art resilientgrips, i.e. the ratio of the thickness of the polyurethane layer to thethickness of the felt layer was a minimum of approximately 0.18, withthe thickness of the polyurethane layer having been about equal to orthicker than the thickness of the textile layer in a typical grip of mydesign. In certain of such grips the handle-abutting side of the striputilized skiving, with the felt layer tapering from a transverse centralregion upwardly and outwardly towards the transverse side edges of thestrip. The side edges of the strip were overlapped as the strip waswrapped around the shaft so that the strip did not have a smoothconfiguration along its length. Additionally, the skiving tended toweaken the grip. Moreover, the side edges of the strip tended to unravelin use. It was also determined that where the strip was not properlyapplied to the shaft, the grip would tend to loosen relative to theshaft. Likewise, prior golf club grips employed caps which failed toadequately prevent unraveling of the grip from the golf club shaft.

SUMMARY OF THE INVENTION

Applicant has discovered that polyurethane and felt golf club shaftgrips of the aforedescribed nature can be made without skiving tothereby afford a stronger, longer lasting grip. Instead, in the grip ofthe present invention the side edges of the strip are butted together asthe strip is wrapped about the golf club shaft. The resulting gripprovides a smoother configuration over the entire grip surface and alsoresists unraveling from the shaft. The improved grip of the presentinvention also incorporates an adhesive material that covers the innersurface of the felt layer to facilitate wrapping the strip about thegolf club shaft and afford increased securement of the grip to the shaftas the grip is used, with the tighter the grasp of the player thetighter the securement of the grip to the shaft. The grip of the presentinvention additionally reduces the manufacturing time and therefore thecost of the grip to the user as compared to prior grips. Moreover, it iseasier to properly wrap the strip onto the shaft so that even an amateurcan obtain a film attachment of a replacement grip to the shaft.

The grip of the present invention also preferably utilizes sidewardlyand outwardly curved reinforcement side edges along its length. Suchside reinforcement edges inhibit unraveling of the grip from the golfclub shaft, enhances the frictional grip of the user and provides animproved appearance over existing grips. This feature also reducesinterference with other golf club grips as club is withdrawn from agolfer's bag. The grip of the present invention may either be used to asa replacement grip, or, alternatively be fabricated as originalequipment by a manufacturer of golf clubs. The grip may include atapered rubber-like sleeve about which the strip is spirally wrapped, orthe strip may be spirally wrapped directly upon the handle portion ofgolf club shaft.

It is an important feature of the grip of the present invention that thegrip includes a unique cap which cooperates with the spirally woundstrip to prevent unraveling of the strip from the golf club shaft bothduring play, and more importantly as a golf club is withdrawn from andreturned to a golfer's bag.

The golf club grip of the present invention has been found to greatlycushion the shock transferred from a golf club to the golfer's body andthereby prevent the danger of injury to the golfer during a golf swing.Yet the golf club grip of the present invention can be made lighter thanconventional grips to reduce the grip weight of a golf club permittingredistributing the weight to the golf club head thereby increasing themoment of inertia with a resulting increase in the distance of travel ofa golf ball. The golf club grip of the present invention can also reducethe total weight of a golf club and thereby permits a higher club headspeed for greater distance of travel of a golf ball.

These and other features and advantages of the present invention willbecome apparent from the following detailed description, when taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a broken top plan view of a resilient strip member of apreferred form of golf club shaft grip embodying the present invention.

FIG. 2 is a broken top plan view in enlarged scale of the strip shown inFIG. 1 particularly illustrating the starting edge configuration of suchstrip.

FIG. 3 is a broken perspective view of a golf club shaft adapted toreceive the grip of the present invention.

FIG. 4 is a broken side elevational view showing the grip of the presentinvention being spirally wrapped about the golf club shaft of FIG. 3.

FIG. 5 is a broken perspective view showing a resilient sleeve appliedto the upper end of a golf club shaft to receive a grip embodying thepresent invention.

FIG. 6 is a side elevational view showing the strips of FIG. 1 and 2being spirally wrapped about the sleeve of FIG. 5.

FIG. 7 is a perspective view showing a cap member of the grip of thepresent invention.

FIG. 8 is a perspective view showing the cap of FIG. 7 inverted from itsposition of FIG. 7.

FIG. 9 is a broken side elevational view showing the cap of FIGS. 7 and8 applied over the upper end of the strip of FIGS. 1 and 2 after suchstrip has been wound about the golf club shaft.

FIG. 10 is a broken vertical central sectional view taken in enlargedscale along line 10--10 of FIG. 9.

FIG. 11 is a horizontal sectional view taken along lines 11--11 of FIG.10.

FIG. 12 is broken central side elevational view similar to FIG. 10, butshowing the strip as applied over the sleeve of FIG. 3.

FIG. 13 is a horizontal sectional view taken along line 13--13 of FIG.12.

FIG. 14 is a view similar to view 13, but showing a modified form ofcap.

FIG. 15 is an enlarged view of the encircled area designated 15 in FIG.10.

FIG. 16 is an enlarged horizontal sectional view showing a heated platenused to form the side reinforcement edges of the strip.

FIG. 17 is a reduced perspective view of a golf club provided with agrip embodying the present invention.

FIG. 18 is an enlarged view of the encircled area designated 18 in FIG.17.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to the drawings, a preferred grip G embodying the presentinvention utilizes an elongated resilient strip S shown in FIG. 1 whichis spirally wrapped about the shaft 20 of a golf club to define a gripG, as shown in FIG. 17. Grip G also includes an annular cap C, shownparticularly in FIGS. 7 and 8, which is telescopically received by theupper end of shaft 20 to restrain the strip S from unraveling relativeto the shaft.

More particularly, grip G includes an open-pored felt layer, generallydesignated 22, having an inner or bottom surface 24 which is adhered toa golf club shaft 20 as shown in FIG. 4, or alternatively to a resilientsleeve 28 telescopically attached to the upper portion of golf clubshaft 20 as indicated in FIG. 6. The smooth closed pore polyurethanelayer, generally designated 30, is bonded to the felt layer 22. Thebonded-together polyurethane and textile layers are seen to beconfigured as the unitary strip S shown in plan view in FIGS. 1 and 2.

The polyurethane layer 30 provides a cushioned grasp of the player'shand on a golf club shaft and also enhances the player's grip byproviding increased tackiness between the player's hand and the grip.The felt layer 22 provides strength to the polyurethane layer 30 andserves as a means for attaching the bonded-together polyurethane andfelt strip to golf club shaft 20. As shown in FIGS. 11, 12, and 15, theunderside or bottom 24 of the felt layer 22 is provided with aconventional adhesive material 36 which covers the underside of the feltlayer. As shown in FIG. 16, the underside of the adhesive material maybe originally covered with a protective quick-release tape 35 which ispeeled off when the strip S is to be applied to shaft 20. Thepolyurethane and felt layers may be formed with vertically extendingperforations 38 which enhance the absorption rate of perspiration from auser's hand.

The felt layer 22 of the strip is formed of a suitable open-poredmaterial and has its upper or outer surface bonded to the lower surface40 of the polyurethane layer 30. As indicated in FIG. 15, thepolyurethane layer 30 is formed with pores 42 which extend vertically,i.e. generally normal to the longitudinal axis of the strip S and golfclub shaft 20 when the grip has been affixed to such shaft. Thepolyurethane layer 30 may be formed in a conventional manner by coatingone side of a felt strip with a solution of polyurethane (e.g. polyesteror polyether) dissolved in a dimethyl formamide (DMF), immersing thecoated strip in water baths to displace the DMF and cause the urethanesto coagulate, and finally driving off the water by the application ofpressure and heat. In this manner, the pores 42 will extendperpendicularly relative to the longitudinal axis of the strip, whilethe underside of the polyurethane layer is bonded to the upper surfaceof the felt strip. As noted hereinbefore, applicant has discovered thatgreatly improved shock absorbing qualities may be obtained in a golfclub grip where the ratio of the thickness of the polyurethane layer tothe thickness of the felt layer is increased over such as employed inprior art grips. More specifically, applicant considers that the ratioof the thickness of the polyurethane layer to the textile layer shouldbe a minimum of approximately 0.18. In the embodiment shown in thedrawings, the thickness of the polyurethane layer is preferably about0.4 millimeters and the thickness of the felt layer in about 0.9millimeters. Excellent results have been obtained with this ratio, sincethe pores 42 permit the polyurethane layer to be readily compressed bythe gripping force of a golfer's hands when making a swing.

In FIG. 16, the strip S is shown being formed with sidewardly andoutwardly extending recessed reinforcement side edges, generallydesignated 46 and 48. The reinforcement side edges 46 and 48 arepreferably formed along the major portion of the strip by means of aheated platen P shown in FIG. 16. Referring thereto, platen P may be ofconventional metal construction having a horizontal base 50 formed atits opposite sides with depending legs 51 and 52. The lower ends of thelegs are configured so as to define and to form the recessedreinforcement side edges 46 and 48. Thus, the lower portion of the legsare provided with like - configured mirror image cavities each having ahorizontally extending surface, the inner portions of which extendupwardly and inwardly, while the outer edges thereof are curvedsidewardly and downwardly. The platen P is heated in a conventionalfashion as by means of electrical resistance elements (not shown) andurged downwardly against the sides of the strip S so as to compress sideportions of the polyurethane layer 30 below the upper surface of suchpolyurethane layer in the manner shown in FIG. 16 to define the recessedreinforcement side edges. Such compression increases the density andhence the strength of the polyurethane layer in the vicinity of its sideedges. It has been found that the width of the recessed reinforcementside edges 46 and 48 may be approximately 2 millimeters, while the depthof the major portion thereof may approximate 0.5 millimeters.

As indicated in FIGS. 1 and 2, the starting end 50 of strip S is cutaway at an angle to define a tongue 51. An inwardly extending notch 52is formed at the inner position of the tongue. The trailing end 53 ofthe strip is also cut away at an angle to define a second tongue 54. Asfurther shown in FIGS. 1 and 2, the tongue and notch dimensions A and Bwill differ depending on the dimensions of the butt end of theparticular shaft receiving the grip.

Referring now to FIG. 4, to apply the strip G to the golf club shaft 20,the quick-release tape 35 is peeled off the adhesive on the underside ofthe felt layer 22. The strip S is then spirally wound around the shaftstarting with the butt or top end of the shaft. As indicated in FIG. 4,starting end (relative to the shaft's butt end) the pointed end oftongue 51 fits snugly within the notch 52 so as to provide a smoothconfiguration of the strip relative to the exterior of the golf clubshaft 20. After the strip S has been completely wound about the shaft 20its lower end may be secured in place by finishing tape (not shown)and/or a conventional resilient ferrule 56 shown in FIGS. 17 and 18 toprevent unraveling of the lower portion of the strip relative to theshaft. Ferrule 56 may be formed of an expandable material such aspolyethylene in order that it can be slipped down the wrapped strip toits position of FIG. 17. It should be noted that tongue 54 permits thestrip's trailing end 53 to provide a smooth transition of the strip tothe golf club shaft.

As indicated in FIG. 15, the reinforcing side edges 46 and 48 of thestrip S do not overlap, and, instead, their radially extending surfacesbutt tightly against one another, as shown at 58. It is important tonote that the abutting side edges of the strip afford a very firmcontact between these side edges, since the polyurethane layer 30 iscompressed by the heating platen P when the recessed reinforcing sideedges are formed in the manner shown in FIGS. 16. Such compressionincreases the strength of the polyurethane material in the vicinity ofthe butt joint. Such firm contact would not be possible if the strip wasformed solely of polyurethane, since polyurethane is quite soft ascompared to felt. Tight abutment of the strip's side edges ensure thatapplicant's strip does not unravel even when the grip is exposed to hardwear during play and when a golf club is pulled out of or returned to agolfer's bag. If desired an adhesive (not shown) may be interposedbetween the abutting side edges, of the grip to further inhibitunraveling. As a result of the aforedescribed abutment, applicant's gripis more durable and hence affords a longer service life than prior artgrips. The provision of the recessed reinforcing side edges 46 and 48further inhibits any tendency of the strip to unravel, enhances theappearance of the grip and improves the frictional contact of the user'shand and the club grip.

Referring now particularly to FIGS. 7-10, annular cap C is of integralconstruction and includes a vertical inner skirt 62, a verticallytapered outer skirt 64, and a horizontal slightly domed cover 66. CoverC is preferably molded from a stiff, synthetic plastic material, such aspolypropylene or polyethylene. A vertically extending expansion slot 68is formed in inner skirt 62. It is desirable that the inner skirt taperat the same angle as the interior of shaft 20 and be tightlytelescopically received by the upper open end of shaft 20. Expansionslot 68 permits a tight fit to be obtained between the inner skirt andthe interior of the golf club shaft even where the outer diameter of theinner skirt is slightly greater than the shaft's inner diameter. Also,the inner diameter of outer skirt 64 should be so dimensioned that itcan tightly telescopically enclose the first wrap of strip S, as shownin FIG. 10. It has been determined that an outer skirt depth of about 8mm for a conventional driver affords good results.

Cap C is secured to the upper end of shaft 20 after strip S has beenspirally wrapped thereabout. It is important that the outer skirt 64extend downwardly a sufficient distance over the upper portion of thewrapped strip to ensure the strip does not unravel relative to the shaftwhen a golf club is being used in play, and particularly when the clubis being removed from and returned to a golf bag by contact with theother golf clubs in the bag. The dimensions of the outer skirt, however,should not interfere with the golfer's grasp of the club. Cap C is seento cooperate with the abutting recessed reinforcing side edges 46 and 48and ferrule 56 to effectively prevent unraveling of the strip from theshaft. Thus, cap C and ferrule 56 prevent movement of strip's abuttingside edges away from one another along the shaft and also preludeunwrapping of the upper and lower portions of the strip wraps relativeto the shaft.

In FIG. 14 there is shown a second form of cap C', wherein the innerskirt 62' is of solid configuration. Such cap can be formed of aresilient material, such as rubber.

Referring now to FIGS. 5, 6, 12, and 13, grip G is shown spirallywrapped about resilient sleeve 28 which has been telescopically fittedover the handle portion of a golf club. The strip S and cap C areapplied as described hereinbefore over such sleeve. It should be notedthat where grip G is directly applied over a golf club shaft the totalclub weight can be reduced as compared to conventional golf clubs. Also,the club weight is redistributed toward the golf club head to therebyincrease the club's moment of inertia with a resulting increase in golfball travel. Conventional grips weight about 53-57 grams, while typicalgrips of the present invention will weigh about 10-13 grams. Thus,direct application of the present grip over a golf club shaft willresult in a savings of grip weight, as much as 43 grams as compared toconventional grips. Alternatively, a cap (not shown) may be integrallyformed on the upper end of the sleeve.

It should be particularly noted that the strip S can readily be replacedwhen it becomes worn or damaged, while the sleeve 28 will remain securedto the golf club shaft 20. The golfer need only remove ferrule 56 or thefinishing tape interposed between the bottom of the original strip, andthen remove the original strip. A new strip is then spirally wrappedabout the sleeve. Finally, a new ferrule or finishing tape is interposedbetween the bottom of the new strip and the golf club shaft.

It should also be particularly noted that with the aforedescribed gripof the present invention the exterior surface of the polyurethane layerprovides tackiness that assures a firm contact of the golfer's handswith the grip at all times. This advantage can be enhanced by theprovision of the perforations described hereinbefore. The use of theperforations not only increases absorption and allows for faster dryingof the grip, but also further enhances a cushioning effect of the gripby providing a controlled restriction of air escaping from within thepores of the textile layer when the grip is grasped by the golfer.

It will be apparent to those skilled in the art that variousmodifications may be made without departing from the spirit of thepresent invention.

What is claimed is:
 1. The combination of a golf club shaft having ahollow interior upper end, and a grip, such combination comprising:astrip consisting of an open-pored felt layer having a generally flatinner surface and a smooth closed pore polyurethane layer having itsinner surface bonded to the outer surface of the felt layer, with thepores of such polyurethane layer extending generally normal to thelongitudinal axis of the strip, and with the felt layer providingstrength for the polyurethane layer while the polyurethane layer bothabsorbs shocks and provides tackiness so as to inhibit slippage of auser's hand relative to the shaft; heat-compressed recessed reinforcingside edges formed in the polyurethane layer of the strip along thelength of the strip; with the strip being spirally wrapped about theupper portion of the shaft to define the grip; a cap formed with aninner skirt tightly telescopically received by the hollow interior upperend of the shaft, an outer skirt that depends downwardly over the upperportion of the strip to restrain the strip against unwinding relative tothe shaft, and a cover integral with the inner and outer skirtsextending over the upper extremity of the shaft; and means interposedbetween the lower end of the strip and the shaft to restrain unwrappingof the lower portion of the strip relative to the shaft.
 2. The grip ofclaim 1, wherein the radially extending surfaces of the recessedreinforcing side edges of the strip are in tight abutment when the stripis spirally wrapped about said shaft.
 3. The grip of claim 1, whereinthe ratio of the thickness of the polyurethane layer to the felt layeris a minimum of about 0.18.
 4. The grip of claim 1, wherein the layersare formed with air-passing perforations that increase perspirationabsorption of the strip and enhance the cushioning effect of the grip byproviding a controlled restriction of air escaping from within the feltlayer when the grip is grasped by a golfer.
 5. The grip of claim 1,wherein the grip weighs about 10-13 grams.
 6. The grip of claim 1,wherein the heat-reinforcing side edges of the strip have a width ofabout 2 millimeters and the heat-reinforcing side edges have a depth ofabout 0.5 millimeters.
 7. The grip of claim 1 wherein the grip-receivingportion of the shaft is flared radially outwardly relative to theportion of the shaft below the grip.
 8. The grip of claim 1, wherein thestrip includes a starting end formed with a tongue and a notch at theinner end of the tongue, with the tongue fitting within the notch whenthe strip is wrapped about the shaft to provide a smooth configurationof the strip relative to the shaft, and with the outer skirt of the capcovering the tongue to restrain the tongue from unraveling away from theshaft, and with the trailing edge of the strip being formed with asecond tongue to provide a smooth transition of the trailing edge of thestrip to the shaft.
 9. The grip of claim 2 wherein the strip includes astarting end formed with a tongue and a notch at the inner end of thetongue, with the tongue fitting within the notch when the strip iswrapped about the shaft to provide a smooth configuration of the striprelative to the shaft, and with the outer skirt of the cap covering thetongue to restrain the tongue from unraveling away from the shaft, andwith the trailing edge of the strip being formed with a second tongue toprovide a smooth transition of the trailing edge of the strip to theshaft.
 10. The grip of claim 2, wherein the layers are formed withair-passing perforations that increase perspiration absorption of thestrip and enhance the cushioning effect of the grip by providing acontrolled restriction of air escaping from within the pores of the feltlayer when the grip is grasped by a golfer.
 11. The grip of claim 2,wherein the heat-reinforced side edges have a width of about 2millimeters and the heat-reinforced side edges have a depth of about 0.5millimeters.
 12. The grip of claim 2, wherein the grip weighs about10-13 grams.